<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
</head>

<body>
    <div id="app">
        <div>
            <p>请选择你要购买的书籍</p>
            <ul>
                <li v-for="(item, index) in arr" :key="index">
                    {{item.name}} <button @click="buyBook(index)">买书</button>
                </li>
            </ul>
            <table :border="1" width="500" cellspacing="0">
                <tr>
                    <th>序号</th>
                    <th>书名</th>
                    <th>单价</th>
                    <th>数量</th>
                    <th>合计</th>
                </tr>
                <tr v-for="(item, index) in arr" :key="index">
                    <th>{{index}}</th>
                    <th>{{item.name}}</th>
                    <th>{{item.price}}</th>
                    <th>{{item.count}}</th>
                    <th>{{item.price * item.count}}</th>
                </tr>
            </table>
            <p>总价格为: {{totalPrice}}</p>
        </div>
    </div>
    <script src="../vue.js"></script>
    <script>
        const app = new Vue({
            el: "#app",
            data: {
                arr: [{
                    name: "水浒传",
                    price: 107,
                    count: 0,
                }, {
                    name: "西游记",
                    price: 192,
                    count: 0,
                }, {
                    name: "三国演义",
                    price: 219,
                    count: 0,
                }, {
                    name: "红楼梦",
                    price: 178,
                    count: 0,
                }, ],
            },
            methods: {
                buyBook(id) {
                    this.arr[id].count++;
                },
            },
            computed: {
                totalPrice() {
                    return this.arr.reduce(
                        (sum, item) => sum + item.price * item.count,
                        0
                    );
                },
            },
        });
    </script>
</body>

</html>